Power wrench



June 30, 1931. c. E. WEAVER i POWER WRENCH FiledApr-il 24. 1930 2 Sheets-Sheet l isis-EE:

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June 3o, 1931. CQE, WEAVER 1,812,816

POWER WRENCH Filed April 24.1930' 2 Sheets-Sheet 2 figg.

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Patented Jupe 30, 1931 UNITED` STATES PATENT' OFFICE- CAIUS E. WEAVER, 0E SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK POWER WRENCH Application filed April 24,

l large structural assemblies and machinery ofmodern times. Heretofore it has been common practice to drill a hole axially throu ha bolt or cap screw, insert a heating e ement therein and expand the bolt or cap screw, then screw it homeo as tightly as possible, remove the heating element therefrom and depend upon the contraction of the bolt or screw as it cools to eiiect the I requisite high tension. Another method has been to use a very large wrench having a long handle, and the power of several men to operate it. The above methods require.

much time and labor, and make it very difcult toobtain a uniformly high degree of tension.l on the screwed parts.

The object of my invention is to rovide `an improved power wrench which 1s porttion, attention is vdirected to the following description and accom anying drawings.

In the drawings whlch represent certain embodiments of my invention, the same reference numerals refer to similar parts in the several views.

Fig. 1 is a perspective View of my wrench and its hydraulic actuating means Fig. 2 is a view, partly in section, ofthe compressor and auxiliary -j devices, certain of the parts being arranged diagrammatically to clearly bring out the relation thereof;.Fig. 3 is a plan view, partly in section, of the power ratchet v,wrench shown in Fig. 1; Fig. 4 is a longitudinal section taken through line 4 4, Fig. 3; Fig. 5 isv a plan view of amodified control valve attached to the wrench, a fragment .of which is shown; Fig. 6 is a longitudinal section ofthe control valve taken through line 6 6, Fig..5;

. Stop 1930. serial No. 447,063.

and Fig. 7 is a transverse section of the valve and wrench taken through line 77,

Fig. 5.

As shown iii-Fig. 1 of the drawings, the wrench is disposed upon the square head of va socket upon a cap screw 9 tobe'screwed home 1n an engine frame 10 to secure a cover plate 11 thereto and the wrench lever 12 abuts against some fixed part, such as a The head of the wrench embodies a ratchet mechanism actuated by a piston and cylinder 14 to which fluid underpressure is supplied through a iiexible pipe V15 from a' hydraulic pressure device 16 supported for plug 13, to prevent it from turning.

free movement about the work independent A of the wrench. Y

The wrench comprises a cast yoke 17, Fig. 3, with the lever 12 extending at one end and having at the other end the means for engaging the part tobe turned, and the ratchet mechanism therefor. forl engaging the part to be turned consists of a rotary sleeve or member 18 provided with a square hole 19 adapted to receive the socket as shown in Fig. 1 and intermediate its ends is an integral ratchet wheel 20,

The means while below the ratchet wheel it is made cylindrical andfjournaled in a bushed bear- 'ing block 21 xed inthe end of the yoke 17,

the extreme end of which is threaded for the reception of a retaining ring 22 ada ted to thrust against the lower side of the carin block 21.. The upper side of the .yoke 1% has its outer edge recessed to vprovide an annular bearing for flange 23 of an oscillating member in the form, of a pawl ring 24 mounted onvthe bearing block and in the plane of the ratchet wheel 20. Formed in the ring 24 are three inwardly opening bearing recesses .for the reception of the pawls 25 -which are yieldingly pressed inwardly` into engagement with the teeth of vthe ratchet Wheel 20 by spring plunger 26 seated in holes through the pawl ring 24 and adjustably retained by screw plugs 27 threaded in the outer ends of the holes.' The pawl ring 24 has a peripheral lug 28 provided at one side with an arcuate thrust seat 29 for engagement of the rounded, outer end of the piston rod 30 of the actuating cylinder 14 and to which it is attached by a cotter held pin 31. In order to retract the pawl ring 24 upon completion of a power oscillation thereof, a spiral spring 32 is attached thereto at its in ner end by a screw post 33 and to the yoke 17 at its outer end by ascrew post 34. In order to retain the spring in position radially, the pawl ring 24 is provided with a circular row of Vertical pins 35. The pawl ring 24, its retracting spring 32, and the pawls 25 are enclosed and held down by a cast washer 36 held in place by one or more diagonal set screws 37 engaging l sup-plied from loosely in an annular groove 38 formed on the upper end of the wrench sleeve 18.

In case the wrench is to be used on a nut or other part of different shape or size, a socket-adapted to iit over the nut or head of the bolt to be tightened can be substituted for the one used, as shown in Fig. 1.

The rear end of the actuating cylinder 14 is provided with a rounded projection 39 adapted to thrust against an arcuate seat 40 formed in a side lug 41 on the yoke 17 and to which it is attached by a cotter held pin 42. The arcuate seats 29 and 40 permit a certain cradling motion of the piston and cylinder 14 during the oscillatory movements of the pawl ring 24 and the cotter held pins 31 and 42 serve merely to prevent disconnection of the parts engaged by them.

The piston 30 and cylinder 14 are of the single stroke type having a single admission and exhaust port 43 for the pressure fiuid and the stroke thereof corresponds substantially to the spacing of the teeth of the ratchetwheel 20. The flexible pipe 15 connects with the port 43 by means of a nozzle 44.

The intermittent hydraulic pressure creating and control means, as shown in Figs. 1 and.2, are mounted on a platform truck 45 with a guard frame 46 whereby movement about the work or from one place to another is facilitated. The intermittent pressurecreating 'means comprises a stout cylinder 16, Fig. 2, with moderate size bore and supported horizontally by a bracket 48 at one end and at the other by a thrust plate 49 connected by tie rods 50 to the compressed air cylinder 51. The flexible pipe 15 connects with the discharge end of the pressure cylinder 16 through abranch coupling 52 to which a pressure gage 53 is attached. The piston 54 of the pressure cylinder 16 is an extension of the piston rod of the compressed air cylinder 51 and is only a fraction of the diameter of the piston 55 of the latter cylinder.

Compressed air or other gaseous fluid is any convenient' source through the iexible hose 56 and a pipe connection 57 to a two-way Valve 58 of ordinary construction provided with an operating handle 59. A pipe 60 connects one way of the Valve 58 to the outer end of the air cylinder 51, a second pipe 61 connects the opposite valve way to the inner end of that cylinder and the third way serves as exhaust from both ends of the cylinder. When the handle 59 is vertical the supply of air through pipe connection 57 is cut off and both ends of the cylinder 51 exhausted; when turned to one side the compressed air is admitted, for instance, to the outer or left hand end of the cylinder 51 and causes its piston 55 and pressure piston 54 to travel to the right and force the hydraulic liquid in the pressure cylinder 16 through the pipe connection -52 and fiexible pipe 15 into the actuating cylinder 14 of the wrench and causing the pawl ring 24 to oscillate forwardly and carry with it the ratchet wheel 20. Upon turning the operating handle 59 from its present position to its opposite position, the exhaust is opened for the ascape of air from the left end of the air cylinder 51 and upon the handle reaching its opposite position compressed air is admitted to the right end of cylinder 51 and the pistons 55 and 54 retracted toward the left and causing the pressure liquid to withdraw from the wrench-actuating cylinder 14 and permitting the spiral spring 32 to oscillate the pawl ring 24 bachwardly. This cycle of operations is repeated until the intermittent pressures and releases ofthe liquid effect a suiiicient movement of the pawl ring 24 to turn home the nut or cap screw 9 under the requisite torque which is indicated by. the pressure gage In order to definitely limit the liquid pressure for the maximum torque to be applied to a particular size of nut or cap screw, a bypass 62, Fig. 2, is provided between the branch coupling 52 and a liquid tank 63 and in this bypass is a regulating pop valve 64 held to its seat by a spring 65, the tensiony of which is adjustable by a screw 66 threaded in the upper end of the valve lcasing 67.

The bypass 62 joins the tank 63 through a cross-connection 68 which also joins the pressure cylinder 16 and a liquid supply pipe 69. The cross-connection 68 communicates with a distributed series of port holes 70 disposed radially through the cylinder walls near the left-hand end thereof, from an annular groove-71 enclosed by a hoop 72. The port holes 70 are closed by the pressure piston 54 at all times except when in extreme retracted or left-hand position and without pressure on the liquid. Any deficiency in the volume of the pressure liquid in the cylinder 16 due either to leakage or discharge through the bypass 62 is restored thereto from the tank 63 which is provided with a piston 73 having a'reduced head 74 operating in a cylindrical extension 75 at the top of the tank 63 by compressed air from sov .the wrench the pipe vconnection 57 whereby suiiicient pressure is maintained in the tank to cause liquid to flow quickly therefrom in case of any deficiency 1n the pressure cylinder 16.

A reservoir 76 supplies liquid through pipe 69 in which are disposed check valves 77 .v and a hand pump? 8 whereby the liquid may be forced into the tank 63 against the compressed lair acting therein. An over# flow pipe 79 leads from the upper portion of the tank back to the reservoir 76.

My -wrench driven by the hydraulic actuconnections shown in Figs. 5, 6 and 7 onf the drawings, and consisting of a three-way valve cylinder 8O fixed by brackets 81 to oke 17 with 4its delivery part 82 connecte by a flexible pipe 83 to the wrench-actuating cylinder 14, the supply port 84 being directly connected by any suitable pipe means to the municipal water supply, while the exhaust port 85 is connected to a convenient drain. The valve rod 86 has a reduced central section 87 and the end sections 88 are adapted to tit snugly in the bore of the valve so that when the valve rod 86 is moved into its eXtreme left-hand position the liquid from the city mains flows through port 84 to delivery port 82 to the -actuating cylinder 14 and upon completion of the wrench stroke a movement of the valve rod 86 into extreme right-hand position closes the supply port 84 and opens the exhaust port 85 so that the pawl, ring 24 oscillates backward under the recoil of its spring 32. The valve rod 86 is manually operated by a hand lever 89 pivotally con# nected thereto and fulcrumed upon la floating link 90 attached to the right-hand end of thevalve cylinder 80.

What I clalm as new and desire to secure by Letters Patent of the United States, is:

'1`. A power wrench comprising a lever, a rotary ratchet member mounted thereon, 'an

oscillating member movable about saidl oscillating member movable about said ratchet member, pawls mounted on. said oscillatin said ratc et member in one direction, a spring connected to said oscillating member to move it in the opposite direction, and a hydraulic cylinder and piston pivotally connected respectively at their outer ends to said lever and tangentially to said oscillat'- ing member. f

3. A power wrench comprising a lever, a rotary ratchet member mounted thereon, an oscillating member surroundin said ratchet member, pawls mounted on sald oscillating member and engaging said ratchet member,

va spring disposed about said oscillatin member and connected respectively to sai mfmber and adapted to move member and said lever and normally acting to hold said 'oscillating member retracted, a fluid-pressure cylinder and piston pivotally connected to said lever and said oscillating member, and means to control the supplyv of pressure fluid to said cylinder.

4. A portable power wrench comprising a lever adapted to be supported on the part to be rotated and to be held from rotation itself by engagement with a stationary abutment, .a circular-shaped head on the supported end of said lever, a polygonal socket rotatably carried bysaid head, an oscillatf ing ring mounted on said head, pawl and ratchet means between said socket and said ring, a hydraulic cylinder and piston respectively pivoted at their outer ends to said lever and said ring, flexible means to supply pressure fluid to said cylinder, and remote means for regulating and controlling the pressure fluid.

In witness whereof I have hereunto set my hand this 23rd day `of April, 1930.

' CAIUS E. WEAVER.

ratchet member, pawls mounted on said oscillating member and adapted to engage said ratchet member, and a hydraulic cylinder and piston pivotall tively at their outer en to said lever and to said- -oscillating member toA actuate the latter. l

2. A power wrench comprismg a lever, a

rotary ratchet member mounted thereon, an

connected respec- -iso 

